The present invention relates to a storage and transportation system suitable for agricultural products including grains such as rice and wheat, or toasted materials such as black tea, for which a high degree of freshness and preservation of flavor are required.
The present invention also relates to a packaging material, packaging container, and package used in the storage and transportation of agricultural products such as rice.
In the long period storage of grains, including white rice, wheat, barley, oats, and rye, corn or varieties of beans, and toasted materials such as treated tea leaves and roasted coffee beans, there are many problems such as deterioration of freshness by oxidation, the loss of their taste and flavor, and decline of their quality by the generation of fungi.
Normally, grains are packed in sacks such as hemp sacks, paper sacks, and plastic film bags. However, with these forms of packaging, the above-mentioned quality problems cannot be adequately prevented.
There are commonly known a method for large volume warehouse storage, the so-called Controlled Atmosphere Storage (CAS), in which freshness is preserved by storage under gases for which the composition, temperature, and humidity are controlled therein, and vacuum storage methods in which a high degree of vacuum is provided therein. However, with these methods, the warehouse becomes large-scale, and the costs go up proportionally, and after the products are taken out of the warehouse and enter the distribution or consumers consumption, the decrease in freshness and quality cannot be prevented.
In addition, it has been proposed that for long distance transportation, the storage room be divided into small scale compartments, and the condition of preservation in each compartment be individually controlled. However, in this case, the preservation and transportation equipment becomes large-scale and after the products are taken out of the storage room, the decrease in its quality cannot be prevented.
On the other hand, in usual packaging, large-sized metal containers and drums has been used. These are very costly, and additionally a non-returnable system cannot be adopted. Because these containers and drums are not transparent, their contents cannot be seen, and the effect from the standpoint of design and appearance cannot be obtained.
In the case of rice which is a representative grain, in the final distribution process and in the stores, this grain is packed in bags of polyethylene film or paper and is sold. In particular, in the case of the bags of polyethylene film, small apertures are made for preventing bursting of the bags, and to provide airing of the bags during storage. Accordingly, in any case, the problem arises that when rice is stored for a long period, its taste and flavor are lost, and it attains an odd smell. In order to provide good storage characteristics, consideration has been given to the use of aluminum deposited film, but this causes an increase in costs and because the film has a fairly thick aluminum layer, there is the inconvenience that the contents in the bag are invisible. Also, such bags are mostly soft, so their decorativeness in the store is destroyed.
There is known a close contact dormancy packaging method in which the rice, which has the property of adsorbing large quantities of carbon dioxide under a high concentrations of the gas, is placed in a bag made of a film which has very poor permeability for carbon dioxide (for example, a lamination of simultaneous biaxially-oriented nylon film and polyethylene film), rice is packaged after the atmosphere is displaced with high purity carbon dioxide gas, and then the bag is sealed. With the close contact dormancy packaging method, in a short period after sealing the package, the rice is flowable, and after a period, the bag is drawn to the inside, and rugged surface configurations on the packaging bag appear. Specifically, close contact dormancy packaging presents the same type of appearance as with the conventional vacuum packaging, and the flowing of the rice is prevented and it becomes hard clumps of hermetically sealed bags.
In this way, when the outer surface of the bag takes on a creased surface appearance, it is not possible to arrive at an effective design to take advantage of the transparency of the package. In addition, if there is some printing on the bag surface, a highly effective display is not possible, and an effective display in the stores is not obtainable. Also, when handling during transportation, storage, and display, some small cracks are formed in the rugged portion and there is some concern that the hermetical seal might be broken.